MSSQL Application Role

I would like to use an application role instead of individual user 
permissions to access a MSSQL 7 database.  Does anyone know how to establish 
a connection in this manner?  The loginString property of the database 
object cannot be used for this.  I tried to use

db.executeSQL("exec sp_setapprole 'role', 'password')

and I get strange results:  the grid object is empty before and after an 
append, but in SQL Enterprise Manager I can see that the new record has been 
added.  Any advice on using the application role would be greatly 
appreciated.